Integrated antenna-receivers, and antenna-transmitters, for millimetre-band, have been discussed in Electronics Letters Vol. 17 No 20 pages 729-730 (October 1981). This article refers to receivers and transmitters which include a planar metal dipole antenna on a body of high dielectric constant material—eg semiconductor silicon, and include an active circuit element—eg a field-effect transistor or a Schottky-barrier mixer diode—incorporated between the dipole limbs, and connected across these limbs.
In order to avoid disturbance of antenna resonance and impedance, resistive loading should be minimal. It is a requirement that the resistive connections provided should exhibit high sheet resistivity at high frequency—ie at frequencies at or near dipole resonance. Eg for a half wavelength resonant dipole on a silicon body, a sheet resistivity in excess of 500 Ω/□ (ohms per square) is desirable. It is a problem producing resistive connections of high sheet resistivity, reproduceably. It is thus a problem producing devices with good yield.
In order to avoid reactive coupling between the antenna and the operative components, it is a further requirement that the contacts should be located at some distance from the antenna metal, ie at locations where the amplitude of the electromagnetic fringe field is minimal—eg at a distance a factor of three or more times antenna dipole width from the antenna.
On the other hand, operative components are in general of low impedance, and if operation is to be optimum this requires that the resistance of each connection, at least at low frequency—eg frequencies from d.c. up to say 100 MHz, according to application—should be as low as is possible. But, for example, a sheet connection, of 500 Ω/□ resistivity, to a contact distant three antenna limb—widths from the antenna, would have a minimum resistance of about 1 KΩ. A lower resistance would be desirable.